Method of producing a watermark design on paper



United States Patent 3,tl43,ldtl lidll'lllltll) 3F PRUDUCENG A WATERMARK DESHGN 6N PAPER llan Machenzie Livingstone, Lyrnington liioad, London 6, England No Drawing. Filed May 25, 1 .9611, der. No. 112,537 5 Claims. (@l. Till-4%) This invention relates to a method of placing simulated watermarks on already manufactured paper, such as stationery, through printing techniques.

The usual method of producing a watermark is by impressing the desired design on the fibres of the paper while the fibres are in a wet state durin" the process of manufacture. The pressure is effected by the design on a dandy roll or press roll and the mark of this pressure appears on the finished paper more translucent than the surrounding paper.

A watermark can at present by applied only to large quantities of paper owing to the difliculties presented by interruptions of the paper-making process, and users of relatively small quantities are denied the possibility of a watermark of their own design.

Various attempts have been made to simulate a watermark by processes applied to paper after manufacture, but they have failed owing to the impermanence of the eifect or to spoiling of the paper.

The present invention is a process by which a permanent watermark effect is obtained by the deposit in the fibres of the paper or fabric after manufacture of a colourless substance rendering the paper or fabric translucent.

The effect is obtained by depositing by ordinary printing processes on paper or fabric a liquid which penetrates the fibres.

The rluid is prepared by dissolving synthetic resin in an organic solvent.

The solvent evaporates during the printing process, having carried and deposited the synthetic resin within the fabric. The proportions to be used in preparing the solution depend on the watermarked effect desired, but will usually be in the ratio of one part synthetic resin to between three and ten parts solvent.

Employment of the proper resin is most important to the practice of the instant invention. Specifically contemplated are the cyclohexanone resins, i.e. the resinous condensation product obtained when cyclic ketones, e.g. cyclohexanone alone, or in admixture with methyl cyclohexanone, are condensed, usually by heating in the presence of methyl alcoholic potash. A particularly appropriate resin is the condensation product of the ketone mixture having two parts by weight of methyl cyclohexanone per one part of cyclohexanone. This cyclic ketone resin is commercialy known as resin AW 2 or Kunstharz AW 2.

For practice of the instant invention preferred solvents for the resin are the aliphatic kerosene fraction hydrocarbons. lvlost preferably a 150 to 206 C. fraction is employed, such a solvent being commercially obtainable under the name of white spirit. If desired, however, any

dfi lddd Patented Aug. 7, lQfiZ of the one to three carbon alcohols (methanol, ethanol, propanol or isopropanol) may be employed alone or in combination with the aliphatic hydrocarbon solvent in the same weight ratio of one part of resin per three to ten parts of solvent.

For better understanding of the instant invention the following specific example or" the practice thereof is presented:

in one quart of white spirit (British standard specification No. 245) five ounces colourless AW 2 resin is dissolved producing thereby a fluid of ink-like consistency, the viscosity being most like that of fiexographic inks. This fluid was employed in a fleXographic printing machine to print a watermark design on already manufactured paper. Once the solvent evaporated the overall result was a translucent effect in the paper quite similar to a conventionally applied watermark. The same results were obtained when ethanol was employed as the solvent.

Since the viscosity of the resin solution may be adjusted by increasing or decreasing the solvent to resin ratio the solution is adaptable to employment as the ink, so to speak, in any conventional type of printing press, e.g., rotary, flatbed, cylinder, bed and platten, job printing press, lithographic press, etc. Both the paper and the fluid can be fed through the press in the ordinary manner. In passing it should be noted that the solvents employed in the practice of the instant invention have extremely high penetrating qualities. I

\F/hile the invention has been described in detail according to the preferred mode of carrying out the process, it will be obvious to those skilled in the art that minor changes or modifications may be made therein without departing from the spirit or scope thereof, as defined in the appended claims.

What is claimed is:

1. A process for watermarking paper which comprises printing on already manufactured paper a watermark design with a fluid essentially consisting of a cyclohexanone resin dissolved in a volatile solvent.

2. The process of claim 1 wherein the volatile solvent is an aliphatic hydrocarbon fraction in the kerosene boiling point range.

3. The process of claim 1 wherein the solvent is a one to three carbon alcohol.

4. The process of claim 1 wherein the solvent to resin ratio varies from 3 :1 to 10:1 parts by weight.

5. The process of claim 1 wherein the resin consists essentially of the condensation product of a mixture con-' taining about two parts of methyl cyclohexanone per part of cyclohexanone.

References Cited in the tile of this patent UNITED STATES PATENTS 1,479,337 Temple Jan. 1, 1924 OTHER REFERENCES De Bell et al.: German Plastics Practice, 1946, De Bell and Richardson, Springfield, Mass. 

